1. Field of the Invention
The present invention relates to the field of detecting melamine content in dairy products, and more particularly, to the method of detecting melamine content in dairy products having different matrixes.
2. Description of the Related Art
Chinese government-issued regulations “Method of Detecting Melamine in Raw Milk and Dairy Products” (GB/T 22388-2008), regulate three methods of detecting melamine in raw milk, in dairy products, and in milk contained products, i.e., high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS/MS), as well as gas chromatography-mass spectrometry [including GC-MS, GC-MS/MS]. Although these methods can facilitate accurate qualitative analysis and quantitative analysis, they can only be performed in labs, due to limitations such as complicated operations, harsh operating conditions, high cost of consumptive materials, and low detecting speed, or the like.
One patent application filed by the China Academy of Inspection and Quarantine has been published with a publication number of CN101477051, entitled with “Raman Spectroscopy for Quick Field Detecting Melamine in the Liquid Milk and Reagent Kit”. The above described patent application discloses one method to quantitatively detect melamine contents in liquid milk using raman spectroscopy. This method mainly studied characteristic curves showing variation of characteristic peak intensity of the raman spectrum of the fresh milk with concentration of the melamine therein, and adopted such characteristic curves and the raman spectrum of the fresh milk to be detected. This can detect the melamine more quickly, and obtain a relatively good detection result with respect to the contents of the melamine in the fresh milk. However, when detecting other kinds of liquid milks, there are some differences between their characteristic curves and those of the fresh milks, since compositions of various different liquid milks will vary. If a quantitative calculation is still done with the characteristic curve of the fresh milks, then it would cause large deviation of the calculation results from the real values. Real measurement indicates that such a method will cause a relatively large measuring deviation upon detecting various liquid milks available on the market. This is mainly because the liquid milks have different compositions and these different matrixes will largely affect the measurement of the raman spectroscopy. Therefore, one of main difficulties for quantitative detection of the melamine in dairy products with raman spectroscopy is to remove interferences caused by different matrixes in the dairy products being measured.
In view of this, there is indeed a need for a quantitative analysis method for quickly and/or accurately detecting melamine content in dairy products having different matrixes.